Knowing how to make a long splice is a must for sailors. Unlike a short splice, a long splice doesn’t increase the line’s diameter, allowing it to pass through a block without jamming.
A broken halyard repaired with a long splice works as easily as before it parted; however, the repaired line will be weaker and should be used only until a replacement can be installed.
A. Carefully unlay the strands of a ¾-inch laid line at least 12 inches. Avoid fraying the ends any more than necessary. If desired, use masking tape or twine to temporarily whip the ends of each strand. Next, intertwine the strands.
B. Loosely tie an overhand knot with strands 2 and 5. Make sure the overhand knot follows the configuration shown. Carefully unlay strand 6 for about 8 inches.
Next, lay strand 3 in the slot created by unlaying strand 6. When strand 3 meets strand 6, tie them into an overhand knot as strands 2 and 5 were tied, but tie this knot tightly.
Now tighten the overhand knot you tied with strands 2 and 5. Examine each strand and its lay to ensure that your work so far is even and equally tight. When this splice is put under tension, each strand must stay in place and take its portion of the load. If they are not equally tight, adjust the tension in the overhand knots to correct the loading.
When you have finished these steps, grasp strand 1 and carefully unlay it for about 8 inches.
C. Lay strand 4 in the slot created by unlaying strand 1. When strand 4 reaches strand 1, tie an overhand knot in these two strands as strands 3 and 6 were tied. Again, make this overhand knot tight and check the strands for even stress under load.
Finally, roll the long splice on the deck to smooth it and make it appear uniform in shape. When you are satisfied with the result, heat-cut the strands and dimple the ends. The final long splice will pass easily through rigging blocks.
Original materials used with thanks to Irene Rodriguez and John Bennett